Fabrication of devices involves the formation of features on a substrate that make up circuit components, such as transistors, resistors and capacitors. The components are interconnected, enabling the device to perform the desired functions. The components and interconnections are formed in numerous layers. Lithography is used to form patterns on the different layers. For example, an exposure source exposes a resist layer using a mask or reticle containing the desired patterns. The resist is developed after exposure, forming a resist mask with the pattern of the reticle. An etch is performed using the resist mask as an etch mask, transferring the pattern to the underlying layer or layers. Numerous masks may be used in the fabrication process of devices.
A mask may contain patterns which are lithographic weak points. Lithographic weak points impact the integrity of the pattern transfer process. The patterns which are weak points need to be enhanced or fixed so that the integrity of the pattern transfer process is not impacted. We have discovered that conventional pattern enhancement techniques are inadequate, particularly with advanced nodes.
Therefore, there is a desire to provide improved pattern enhancement to improve pattern transfer integrity.